In wiper blades for windows of motor vehicles having an elongated, spring-elastic support element for an elongated rubber-elastic wiper element, the support element should assure the most uniform possible distribution of the wiper blade contact pressure, originating in the wiper arm, on the window, over the entire field swept by the wiper blade. By means of a suitable curvature of the unstressed support elementxe2x80x94that is, when the wiper blade is not resting on the windowxe2x80x94the ends of the wiper strip, which in wiper blade operation are pressed fully against the window, are urged toward the window by the then-tensed support element, even if the radii of curvature of spherically curved vehicle windows vary for every position of the wiper blade. The curvature of the wiper blade must accordingly be somewhat greater than the greatest curvature measured in the wiping field of the window to be wiped. Thus the support element replaces the complicated support bracket construction that has two spring rails disposed on the wiper strip, as in conventional wiper blades (German published, nonexamined patent application DE-OS 15 05 357).
In a known wiper blade (German Patent 12 47 161), the rigid coupling part toward the wiper blade is solidly riveted to the support element, so that the support element is fully reinforced in its center portion. The contact face between the support element and the underside of the coupling part thus extends over the entire length of the coupling part, so that this portion cannot contribute to adapting the wiper strip to the course of the window surface. A teaching similar to the invention can be learned from an exemplary embodiment of the known wiper blade, except that there, no information is provided that the reinforced enter portion of the support element or any provisions for overcoming this drawback.
In the wiper blade of the present invention, a criterion is met that limits the reinforcement of the center portion of the support element to what is still tolerable without major disadvantages.
In a wiper blade in which the joint between the coupling part and the counterpart coupling part has pivot pins guided in bearing recesses, an even better adaptation of the wiper strip to the course of the window surface is attained if the contact face between the support element and the coupling part, measured in the longitudinal direction of the wiper blade, is less than the diameter of the pivot pins.
An optimal adaptation of the wiper strip to the course of the window surface is obtained if the contact face between the support element and the coupling part is equivalent to a line that extends in the direction of the pivot axis and is located inside the projection area of the pivot pins. As a result, the support element does not undergo any stiffening from the coupling part, so that the entire length of the support element can be used for adapting the wiper strip to the course of the window surface.
For proper alignment of the coupling part on the support element, the coupling part has a U-shaped cross section, and the inside of the base of the U forms the underside of the coupling part, and the spacing between the two legs of the U from one another is adapted to the existing maximum width of the support element in the longitudinal center portion of the support element.
In a further feature of the invention, on the free end of each leg of the U, and spaced apart from the underside of the coupling part, attachments oriented in clawlike fashion toward one another, which form bracing means for the support element, are disposed at least in the region of the contact face between the support element and the coupling part. The spacing is dimensioned such that when the curved support element is introduced, it rests on the attachments with its lower band face under tension at two points spaced apart from one another, and that it is braced with the apex region of its upper band face on the underside of the coupling part. This bracing is linear and is oriented crosswise to the longitudinal extent of the support element.
An advantageous embodiment of a support element belonging to the wiper blade that can also, however, be used independently in wiper blades of a different design, provides that the coupling part has a carrier of U-shaped cross section and made of metal, whose outer walls are covered by means of an envelope of U-shaped cross section made from a plastic; and that furthermore pivot pins that belong to the swivel connection between the wiper arm and the wiper blade are disposed on the outer walls of the legs of the U of the envelope. The metal carrier guarantees reliable wiper operation even after a relatively long time in operation, while in the choice of material for the envelope, the demand for wiper blade support on the wiper arm can be taken into account.
If the metal carrier has bending tabs that are joined to the base of its U and that fit over the two longitudinal outer edges of the support element, then the coupling part can be joined in a simple way to the support element, or in other words firmly clamped to it, by means of these bending tabs.
Fastening the plastic envelope to the metal carrier is possible in a simple way by detent locking of the envelope, if the envelope, made of an elastic plastic, protrudes with its legs of the U past the legs of the U of the carrier; and that detent hooks protruding toward one another are disposed on the free ends of the legs of the U of the envelope. In a wiper blade, in which the coupling part is provided with pivot pins, protruding transversely to the longitudinal extent of the wiper blade and belonging to the swivel connection between the wiper arm and the wiper blade, which pivot pins are disposed on the end portion of the coupling part remote from the drive side of the wiper arm, it is possible for a spoiler, for instance, disposed on the side of the support element remote from the window, to be brought with a leading face, facing into the relative wind, to near the pivot connection, which enlarges this leading face and furthermore prevents an unattractive gap from forming between the joint and the spoiler. It is understood that the application of this feature of the invention can be employed independently of the invention, wherever a suitably designed coupling part of the wiper blade is used.
In a wiper blade having a longitudinally split support element, both of whose longitudinal edges toward one another rest in lateral longitudinal grooves of a top strip connected to the wiper strip, the mounting of the coupling part can be accomplished in a simple way if in a further development of the invention, the coupling part is split longitudinally of the support element, and each of the two coupling part halves is provided with a longitudinal groove, oriented toward the respectively other coupling part half, for receiving a longitudinal strip with the longitudinal edges, remote from one another, of the two support element parts, and the two coupling part halves can be joined to one another.
An especially sturdy connection of the two coupling part halves to one another is attained if at least one of the two coupling part halves, made of an elastic plastic, dips with a fingerlike protrusion, fitting over the longitudinal center portion of the support element, into a recess that is present in and associated with the other coupling part half.
To simplify mounting, it is provided that the protrusion is provided, near its free end, with a detent shoulder pointing toward its coupling part half, which shoulder cooperates in detent fashion with the long side, toward it, of the top strip.
The two coupling part halves can no longer be separated unintentionally from one another if a lug disposed on the free end of the protrusion, dips into a recess of the other coupling part half.
An especially stable design of the coupling part is attained if the tongue- or fingerlike protrusions of one coupling part half are provided with lateral splines, with which guide grooves in the other coupling part half are associated.
So that the coupling part cannot be displaced on the support element longitudinally thereof, the support element, in the region of the coupling part, is provided with a lateral protrusion, with which a recess in the inside, toward this side, of the coupling part is associated.
A connection between the wiper blade and the wiper arm that is very reliable in operation is obtained in a wiper blade, which in its longitudinal center portion has two pivot pins, aligned with one another and forming the pivot axis, which are guided in bearing recesses of the wiper arm, if each bearing recess has a mounting channel, each associated with one pivot pin and being open toward the window.
Further advantageous refinements and features of the invention are disclosed in the ensuing description of exemplary embodiments shown in the associated drawing.